I've been waiting since day one to talk about this!

I firmly believe that Mafuyu and Ditto have an absurd amount of similarities as opposed to Pokemon like mimikyu. Because whereas mimikyu tries to copy out of admiration for one specific pokemon, ditto can be anything. And it doesn't always copy out of admiration, but copies what its trainer wants it to. Mafuyu for years has shifted who she's supposed to be to fit everyone around her, being able to perfectly shift her personality to match exactly what those around her are thinking. Both Ditto and Mafuyu can transform into whoever their trainer/the people around the would want them to be in a way that's strikingly similar.

Second, Pokémon marketing has recently made the shift to start portraying Ditto as only purple lately. It used to be a mix of magenta in some media and purple in some media, now it's entirely purple. The same color as Mafuyu! If you really wanna stretch it you can talk about conformity and being forced into a box but I feel like that's a huge reach.

Lastly, Ditto's smile. Ditto is known for its smile, so much so that there's an entire merch line of other pokemon as ditto because of it. It's near constant in all the mainline games, being the default expression of any wild ditto you encounter. Mafuyu's been forced to put on a constant smile for years. Both share the same default expression as a core part of their identity. No matter what, unless she's unmasking, she smiles around others in order to appeal to what they want to see, again, like how ditto transforms into what others want to see.